The present disclosure relates to a power amplifier circuit. In cellular phone devices, smartphones, and the like, a power amplifier is used for amplifying radio frequency (RF) signals (see Satoshi Tanaka, “Evolution of Power Amplifier for mobile applications”, the Institute of Electrical and Electronics Engineers, Inc. (IEEE) 2013 International Meeting for Future of Electron Devices, Kansai (IMFEDK 2013), June 2013, pp. 112-113).
In general, in a power amplifier circuit, when output power is at its maximum value, efficiency reaches its maximum value. Thus, when the output power is below its maximum value, the efficiency is below its maximum value. For example, an average value of the output power is below the maximum value of the output power. Hence, the power amplifier circuit may not achieve desirable efficiency over a wide output power range.